Embodiments of the invention relate to a method and device for detecting the presence of a trailer or semi-trailer of a motor vehicle.
Stability is a primary concern for a vehicle towing a trailer, especially when the vehicle towing the trailer is traveling at high speed or making a turn. Since the trailer significantly affects the dynamics of the towing vehicle, many control systems use techniques to improve the stability of the towing vehicle especially when a trailer is present. For example, systems such as anti-lock braking system (“ABS”), tire control system (“TCS”), and vehicle dynamics control (“VDC”) are configured to perform different functions for the vehicle and the trailer in order to improve stability. Furthermore, the towing vehicle can better control its transmission if the presence of a trailer is known.
Existing methods used to detect the presence of a trailer generally require additional sensors and hardware to be installed on the towing vehicle. In some cases, the vehicle can require additional hardware including electronic circuits and relays, which can increase the cost of the vehicle and/or trailer. In some other cases, the towing vehicle uses a current measurement of its brake lights to detect the trailer presence. In some other cases, signals from an electronic stability program (“ESP”) are used to detect a trailer oscillation (the program assumes that a trailer is present).